1. Field of the Invention
The present invention relates generally to packaging machinery and methods and, more specifically, to a method and apparatus for securing a lid to a cardboard box that has previously been loaded with a product.
2. Description of the Prior Art
A large number of machines exist at the present time which are capable of applying and securing lids to open top cartons as well as for folding and securing the initially open top flap or flaps of cartons filled with product. The existing devices include machines which serve to apply and form prescored lids about the openings of open-top cartons. Quite frequently, lids are presented to filled cartons in the form of prescored blanks having planar configurations. When the carton is of an open-top variety the blanks are extended across the carton top openings and then down-folded along score lines in a manner such that the peripheral portions of the lids engage the vertical side walls of the cartons.
In another type of packaging method, the top closure is provided in the form of a top flap or flaps developed from and integral with the container. Since the closure is integrally formed with the container, a mere folding operation is required to position the top flap or flaps over the initially open top.
In either type of packaging operation, it is customary to move empty cartons along a path on some type of conveyor system or by gravity in a chute. The cartons are either provided with closed integral side walls in an earlier carton forming operation, or the carton is formed as it moves down the conveyor line. As the cartons proceed along the path, product is placed in the carton. In the first method described above, a lid is applied to the open-top carton and the lid peripheral edges are folded and secured to the carton sidewalls. In the second of the previously described methods, the carton has an integral open top flap or flaps. The open top flaps of the carton are folded to make a closed top wall for the carton and the folded flaps are then secured to the sidewalls of the carton.
It is highly desirable that the previously described loading, closing and fastening operations proceed at a high rate of production. Continuous and reliable high speed loading of the cartons, applying of lids and closing of the top flaps is generally achieved at the present time, but the step of securing the carton top slows down the entire operation. For example, it is common at the present time to fasten the lid or top flaps by gluing them to the side walls of the carton. In addition to the start up and break down delays involved in handling glue, which is sticky and susceptible of change in viscosity during periods of inactivity, extra traveling space must be provided along the loading path to permit adequate time for the glue to set up and cure. This can result in a lower production rate. Perhaps more importantly, the cost of the glue used in the step of securing the carton top is a major expense in the overall packaging operation.
In order to overcome the disadvantages of gluing, cartons have been devised with tongues on certain flaps which cooperate with notches or grooves in other flaps of the carton. The tongues are engaged and forced into a locking fit in the grooves or notches in order to secure the carton top. See, for example, U.S. Pat. No. 2,937,486, to Ackley, issued May 24, 1960. This approach decreases some of the difficulties associated with gluing. However, the prior art devices known to Applicant which use punches, and the like, introduce other problems into the packaging operation. For example, in the case of cartons containing plastic milk jugs or cartons, the punch apparatus must operate within strict tolerance control. Otherwise, the punching procedure may tend to bruise or buckle the cartons because of misalignment of the punches and also because of the required speed of the punches necessary to fasten the cartons as they move along the path. In a worst case scenario, the punch may actually puncture the jug or milk carton.
It is therefore an object of the present invention to provide an improved apparatus and method for folding and securing the initially open flaps of an open-top carton to the main body of the carton to thereby provide a secure closure for the carton.
Another object of the invention is to provide such an apparatus and method which can be used to secure separate carton lids to an open top carton.
It is another object of the present invention to provide a device of the character stated which is extremely versatile in usage being adapted for integration with a variety of assembly line operations and, hence, be readily incorporated into existing equipment without requiring costly modifications.
It is a further object of the present invention to provide a device of the character stated which incorporates a minimum of additional components and which is readily adapted for automatic operation in cooperation with any of a number of suitable hydraulic or pneumatic power drive sources and which is, hence, capable of operating at predetermined rates commensurate with a particular packaging operation so that it does not impede or restrict the designed volume flow of the related equipment.
It is a still further object of the present invention to provide a device of the character stated which can be economically manufactured, which is resistant to breakdown, and which is extremely durable and reliable in usage.
Additional objects, features and advantages will be apparent in the written description which follows.